/*
 * Copyright 2021 <copyright holder> <email>
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef RANDOM_H
#define RANDOM_H

#include <math.h>
#include <stdlib.h>

inline double RandDouble()
{
    double r=static_cast<double>(rand());
    return r/RAND_MAX;
}

inline double RandNormal()
{
    double x1,x2,w;
    do{
        x1=2.0*RandDouble()-1.0;
        x2=2.0*RandDouble()-1.0;
        w=x1*x1+x2*x2;
    }while(w>=1.0||w==0.0);

    w=sqrt((-2.0*log(w)/w);
    return x1*w;
}

#endif // RANDOM_H
